Anti-relaxation performance of martensitic chromium stainless steel 3Cr13

Introduction

Ferritic chromium martensitic stainless steel (3Cr13) is a martensitic stainless steel with a chromium content of 12-14%. Martensite is a form of iron alloy with a body-centered cubic structure. It is hard, brittle and strong at room temperature, and can be used to make cutting tools and other wear-resistant objects. Martensitic stainless steels are classified into two groups: high-carbon (C > 0.6%) and low-carbon (C < 0.2%). 3Cr13 is a low-carbon steel with good mechanical properties, good corrosion resistance, good toughness and excellent wear resistance. This paper discusses the stress relaxation properties of 3Cr13 stainless steel.

Analysis of Stress Relaxation in 3Cr13 Stainless Steel

Stress relaxation is an important property of engineering materials, which determines the materials ability to absorb energy and impact loading. Stress relaxation properties of 3Cr13 stainless steel were studied by two methods: static loading and fatigue testing.

Static loading test

The static loading test is used to measure the strain rate during loading and unloading of the material. A specimen is loaded until a certain load level is reached. The loading is then released, and the rate at which the specimen returns to its original state is recorded. The data is then used to calculate the stress relaxation of the material.

Fatigue testing

Fatigue testing is used to measure the strain rate during cycling loading and unloading of the material. A specimen is subjected to a series of cyclic loading and unloading, at increasing load levels. The loading is then released, and the rate at which the specimen returns to its original state is recorded. The data is then used to calculate the stress relaxation of the material.

Result

The results of the static loading and fatigue tests showed that 3Cr13 stainless steel had excellent stress relaxation properties. The stress relaxation rate under static loading and cyclic loading increased with increasing load level, indicating that the material could absorb increasing amounts of energy with increasing loading. The results also showed that 3Cr13 had a higher stress relaxation rate under cyclic loading than under static loading. This indicates that the material can absorb more energy when subjected to cyclic loading than when subjected to static loading.

Conclusion

The study showed that 3Cr13 stainless steel had excellent stress relaxation properties. The stress relaxation rate could be increased with increasing loading level by both static and cyclic loading. The results indicate that this material can absorb large amounts of energy and impact loading, making it a suitable material for a variety of engineering applications.

Martensitic chromium stainless steel 3Cr13 has good comprehensive mechanical properties, high strength and hardness (up to HRC 34-40, equivalent to SUS420J2 or AISI420), with good corrosion resistance, toughness and wear resistance properties. The temperature of maximum strength and hardness for 3Cr13 is about 500°C. 3Cr13 is generally used in production of complicated molds, stainless screws and nuts and some rubber roller and other demanding parts, such as medical instruments, kitchen tableware, food processing machine, industrial equipment etc.

In terms of anti-relaxation performance, 3Cr13 is usually treated with heat treatment processes such as tempering and annealing to reduce its strength and elongation, thus enhancing its anti-relaxation performance. For example, it can be quenched in a salt bath at 980-1000℃, and then the temperature can be transferred to 840-870℃ to bring it back to the martensite state. After quenching and tempering, the hardness of 3Cr13 can be improved to HRC50, with higher tensile strength and good fatigue resistance. After surface grinding and low-temperature tempering, it also has a high precision and clear surface, making it suitable for products requiring higher precision surface.

Therefore, with good anti-relaxation performance, 3Cr13 is usually used for the production of high precision molds, stainless steel screws, nuts and some rubber rollers, providing reliable quality.